The present invention relates generally to an inspection system and method for underground power line inspection.
Underground power lines require inspection and maintenance to ensure long-term performance and reliable operations. Inspection and maintenance access is typically obtained through vaults (manholes) or tunnels, FIGS. 1-5, through which the lines run. Conventional inspection practices often involve human entry to the vault or tunnel and require utility personnel to have direct access to the line components for visual inspection and/or necessary measurements using portable instruments, FIGS. 6 and 7. However, certain sections of the underground lines may be difficult to access or there may be restrictions to get access which may require taking the entire circuit out of service and/or entail significant personnel safety hazards. Examples include components in underground splice vaults where the space is confined with potential hazards.
Entering a confined space with potential hazards is restricted by many electric utilities. As a result, inspection personnel cannot easily or safely access certain sections of underground power lines. In many occasions, getting access to those sections or areas is costly. For example, line outages are required by many utilities for personnel to enter an underground vault for inspection. In some instances, inspection for these areas may be performed with the assistance of extension sticks or moving carts. However, such inspection methods can be limited and difficult to standardize.
Under a limited scope, inspection may also be performed using remote sensing. In this sensing technology, sensors are fixed at specific locations adjacent to or near the components to be inspected. The measurements are then made, and data retrieved and processed on site or transferred to a remote location. However, because remote sensing devices, if used, are fixed at specific locations within the vaults, they may not have full view of all components, thereby limiting the effectiveness of the inspection.
Accordingly, there is a need for an underground power line vault inspection system and method that allows complete inspection of an underground power line without compromising personnel safety or performing a costly line outage.